A039635 Fixed point of "n -> n/2 or (n+1)/2 until result is prime".

1, 2, 3, 2, 5, 3, 7, 2, 5, 5, 11, 3, 13, 7, 2, 2, 17, 5, 19, 5, 11, 11, 23, 3, 13, 13, 7, 7, 29, 2, 31, 2, 17, 17, 5, 5, 37, 19, 5, 5, 41, 11, 43, 11, 23, 23, 47, 3, 13, 13, 13, 13, 53, 7, 7, 7, 29, 29, 59, 2, 61, 31, 2, 2, 17, 17, 67, 17, 5, 5, 71, 5, 73, 37, 19, 19, 5, 5, 79, 5, 41

Offset

1,2

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Mathematica

upp[ n_Integer ] := FixedPoint[ If[ EvenQ[ # ]&&#>2, #/2, If[ PrimeQ[ # ]||(#=== 1), #, (#+1)/2 ] ]&, n, 20 ]

Prog

(Haskell)
a039635 1 = 1
a039635 n = until ((== 1) . a010051) ((flip div 2) . (+ 1)) n
-- Reinhard Zumkeller, Nov 17 2013

Crossrefs

Cf. A039634-A039645.

Cf. A010051, A039637, A039634, A039640, A039641.

Sequence in context: A285708 A072593 A348907 * A303077 A347619 A164858

Adjacent sequences: A039632 A039633 A039634 * A039636 A039637 A039638

Keyword

nonn

Author

Wouter Meeussen

Extensions

Offset corrected by Reinhard Zumkeller, Nov 17 2013

Status

approved